Knife sharpener



J. A. GRoBsTElN 2,077,689 i KNIFE SHARPENVER Filed March 4, 1935 I5 Sheets-Sheet 1 April 20, 1937.

April 20, 1937- J. A. GRoBsTl-:IN

y KNIFE SHARPENER Filed March 4, 1935 s'sheets-sheet 2 illy.: |19

April 2o, 1937.

J. A. GROBSTEIN KNIFE SHARPENER Filed March 4, 1935 3 Sheets-Sheet 5 Patented Apr. 20, 1937 UNITED STATES PATENT OFFICE KNIFE .SHARPENER Julius A. Grobstein, Chicago, Ill.

:Application March 4, 1935, Serial No. 9,168

23 Claims.

My invention relates to an improved method and means for `v'sharpening knives. 'particularly knives employed by furriers.

In the fur industries, it is customaryinniaking fur garments fand the like to -cut the :fur skins sometimes into relatively .small pieces for the purpose not onlyof ittingthe garment, butzalso for the purpose vof matching the fur as to color, texture, andthe like. A fur cutter, therefore, Will work for long periods :fat-atimecutting skins with a specially vdesigned Vhand fur knife lWell known in theindustry. VOn account vof theextensive use to which the yknifeis put, it requires frequent sharpening. Heretofore, no .suitable means forsharpening these 'knives 'has been known -except fa -small :stone which the cutter employs by hand, and a leather .honefor finishing .the iedge. Not only .does this ,hand sharpening require a vconsiderable part of the furriers time, but veryfew cuttershave the ability toproduce a good edge and :the useof fa knife which is improperly sharpened further .complicates the work.

YThe object of my invention is the provision of an inexpensive' sharpening tool .specially adapted for applying-a .necutting edge to the usual type'of fur knife.

.Another object is the provision of an inexpensive instrument which may be ,adapted .for sharpeningother types of knives suchas detachable blades sometimes employed :in urriers knives.

Another object is lthe provision of means for pointing fur knives and similar knives.

Other objects and `features of Ymy invention will be vapparent from -theifollowing description `taken with `the accompanying drawings, wherein Fig. 1 .-is a transverse sectional view vof one embodiment fof my invention, some ofthe parts Abeing in elevation, the view being taken substantially along the line l-I of Fig. 2, Alooking in the direction of the arrows;

Fig. .2 is Aa longitudinal sectional viewzshowing some of the yparts in elevation;

Fig. 3 is va. ,plan view, .partly in section;

Fig. 4 is. a fragmentary ,plan view showing :the sharpening elements;

Fig. 5 is an enlarged fragmentary sectional viewpartlyin elevation takenon the line -5--5 of Fig. 3, but .showing the .parts in modified position;

.Figs and .7 show modified types of knives employed by furriers; and

Fig. 8 .showsan adapter foruse when sharpen- .ing such blades as thOSeshown inFigs. 6 and -7.

According to the general provisions of my invention, I provide a movable carriage adaptedr to receive a fur knife, so arranged that when the fur knifey is in position and the moto-r operated, vthe carriage will advance and carry the knife along a predetermined path in contact with a pair of sharpening elements of special design. The sharpening elements are of a composite type in the form of a pair of co-acting wheels of special shape Yprovided with a plurality of stone sharpening sections and co-acting leather stropping sections. The knife and sharpening members are so disposed with respect -to each other that the stone portions first engage the Vknife edge while moving in a. generally downward direction, .and the stropping portion, preferably made of .leather thereafter vengages the portion of the blade which the stone .portions have engaged to finish the sharpening action. The mechanism is vdesigned so that when the knife hasmoved along Vits ,predetermined path and all portions of theedge have been sharpened, the operating mechanism is automatically stopped, .and the knife and `carriage are returned Yto the starting position and the knife is readily removed for use.

Referring .now .to the drawings, I show a frame comprising a main Ybase lplate Ill, end plates .Il and I2, and side plates I3 and I4. Base plate I0 extends beyond the end plate I2 and adetachable angle plate I6 is provided, affording a housing for adriving motor ,I1 (Fig. 3). The driving motor .has a shaft I8 extending from both ends thereof `carrying apair of bevel gears I9 and2l meshing with bevel gears 22 and 23, `respectively. These two bevel gears are pinned to shafts 24 yand 26, journalled in end plate I2, and carrying bevel gears 21 rand v28 vmeshing with gears 3l and 29 on shafts 33 Vand 32, respectively. It is these two shafts which .drive the sharpening members adjustably .carried thereon in a manner to be described.

Secured to base plate I0 are a pair of uprights 34 and 36 in which the shafts 32 and 33 respectively are journaled. v"I'hese shafts carry sharpening .members -31 and 38, each having a composite construction Ywhich will be described. For convenience, the support for the sharpening member 38 will be described first, the construction being the same in each case.

Shaft 33 4has a non-circular portion 33a provided with a sleeve 39. The sharpening `member 38 xis secured yon a threaded portion of vthe sleeve between .nuts 4I and 42, a washer 43 being ,provided. Sleeve 39 has a ange 44 anda compression spring 46 is disposed around the sleeve and p engages between the flange 44 and an adjusting member 41. The second spring 48 is compressed between the adjusting member 41 and the nut 42. The adjusting member 41 is pivoted at 49 and a spring 5| urges the adjusting member in a clockwise direction around its pivot, looking at Fig. 1. An adjusting rod 52 has a nut 53 intermediate its ends on a threaded portion, and the end thereof extends into an adjusting member complementary to and co-acting with the adjusting member 41. The end of the rod 52 is shaped to receive a suitable tool to permit turning.

The knife to be sharpened is indicated by the character 54, and this knife is supported between sharpening members on a carriage which progresses it longitudinally to present all portions thereof to the sharpening members. The manner in which this knife is supported will now be described.

The top of the machine comprises a cover plate 56, the center of which is recessed longitudinally of the machine to receive a slidable carriage 51. Within the carriage is an adapter 58 adapted to hold the knife 54, or to support a modified form of knife, as will be described later. At the top of the carriage are a pair of brackets 59 and 5| in which are journaled the ends of a general U-shaped rod 62, to the middle portion of which is attached a block 63 carrying a handle 64. The U-shaped rod 62 is provided with a spring 66 which normally tends to hold the rod and handle in an upright position, as shown in Fig. 5.

At one end of the rod, the carriage is provided with a pair of brackets 61 in which is journaled a pin 68 carrying a latch 69, in the form of a bell crank lever. upper portion 69a and a lower portion 69h. A spring provided on the pin 68 moves the bell crank lever in a counter-clockwise direction, looking at Fig. 2. The end of the U-shaped rod 52 is slotted so that when it is moved to the positicn shown in Fig. l., the upper portion 69a of the latch engages in the slot and prevents the return of the handle to the upper position. The manner in which this latch is released will be described in a later portion of the specification.

The vlower portion of the carriage 51 is provided with a plurality of brackets 1| and 12 through which rods 13 and 14 extend, and on which rods the carriage is adapted to move when propelled by means which will be described hereinafter. The ends of the rods are generally U- shaped and are fulcrumed in brackets 16 supported on the under side of the cover plate 56. Looking at Fig. 2, spring 11 tends to move the rods in such a direction as to hold the carriage 51 in a downward position. The rods also have collars 18 which are engaged by one end of springs 19 extending around the rods. The other end of the springs 19 engage followers 8| provided on the carriage.

As shown in Fig. 5, the carriage 51 is provided with wells in which compression springs 82 are placed, one end of the springs engaging the bottom of the wells and the other end engaging pins 83which extend up and are adapted to be engaged by the adapter 58. When the handle 64 is pressed down, the springs 82 are compressed, but on release of the handle they expand and cause the adapter to spring upwardly so that it is easily removed.

For removing the knife shown at 84 from the adapter (Fig. l), I provide a pair of springs 86 which are set in recesses on opposite sides of the adapter and engage along the tapered sides of This bell crank lever has an the knife. When pressure is removed from the top of the knife, these springs cause the knife to be forced upwardly a sufficient distance to permit the fingers to grasp a relatively wide portion of the knife indicated at 85a.

Although the knife is in general provided with suihcient support by the carriage, I provide an additional centering means in the form of a pair of grooved rollers 81 and 88 journaled on shafts 89 and 9| carried on uprights 92 and 93. These grooved rollers function to protect the edge of the knife and also to hold it more securely during the time that the leading and rear edges of the knife are in contact with the sharpening members.`

I provide means for moving the carriage and knife carried thereby longitudinally of the machine during the sharpening operation. The mechanism employed for this purpose is of such a character as to permit ready return of the carriage to the starting position when it is advanced to its extreme of travel. The specific embodiment which' I show for securing this result is as follows:

Secured to shaft 24 is a worm 94. is'adapted to engage a rack 96 carried by an arm 91 pivoted to the rod 14 but constrained to move with the carriage. This arm 91 has an offset 98 (Figs. 1 and 5), with a cam-like edge engaged by a roller 99 journaled in the end of a bell crank lever |9|. This bell crank lever is pivot-ed in the carriage at |02 and has one end adapted to be depressed by a pin |03 when the handle 64 is lowered. A spring |04 is interposed between the pin |03 and the bell crank lever |0| to allow for difference in the adjustment of the parts. A spring |06 is attached to the carriage and to the arm 91, normally tending to hold the rack 96 out of engagement with the worm 94.

The motor |1 is controlled by a switch |01 provided with push buttons |08 and |09. Push button |08 is manually operated and can be reached from the outside of the machine. Push button |09 is in the path of arm 91.y When the rack 96 reaches its limit of travel, push button |09 is depressed and the motor is stopped.

The general structure of the sharpening members 31 and 3B should be clear from the drawings. In general, however, I provide a frame 39a, preferably formed of metal, a stone portion 3817, and a leather edge 38e. Elements 31a, 31h, and 31o represent similar parts on sharpening member 31. The relative size of the stone and leather may be modified, but as will be shown in the description of the operation of the machine,

each portion is able to perform its own function independently. It will be understood that in place of stone and leather, I may substitute other materials, the portion 38hbeing the sharpening portion and the portion 38C the stropping portion. It will be seen that there are three sharpening sections or lugs on each one of the sharpening members (see Fig. 2). These portions engage the knife successively, alternating between the two sharpening members. The use of this arrangement'permits placing the sharpening wheels at an angle to each other to produce the proper sharpening action.

At the end of motor shaft I8 and exteriorly of the machine, I provide a. sharpening stone Adjacent the sharpening stone I provide a bypart knife holding frame ||2 pivoted at ||3 and provided with a handle l I4. As shown in Fig. 3, the knife may be supported in such a manner as to repoint it should the point be broken off for This worm:

any reason. After the knifecis repointed, it-may have its edge sharpened by themechanism previously described.

I provide suitable means for introducing oil vor other fluid to vthesharpening Amembers to facilitate sharpening. Asshownin Fig. 1, the bevel gear v28 meshes with a bevel gear H6 secured on an upright shaft H1. The lower .portion of this shaftdrives a pump, one vgearof which iszshown at IIS. Oil'in `suitable quantities is withdrawn from a sump and delivered through a pipe H9, whence 4it is fed to the .knife at the point where the sharpening .members engage it.

The yoperation `.of .the ,machine yis :as follows: The `knife 84 is placed in vposition iin the ,adapter and the 'handle moved Ldownwardly to hold Ithe adapter vin position and lto fcause theirack @Sito vengage the worm 94. The .switch l08.is -then pressed and :the motor is roperated rand 'through the :gear mechanism described, 1drives the two sharpening members. These two isharpening members `engage the .knife in approximately the Jposition indicated by the character yAin `Iig..2, the sharpening members being rotated .in the direction indicated by the arrow. The knife Vimmediately starts to move inthe direction indicated by therarrow vin Fig. v2 placed on the body of theIknife. First .one sharpening member engages .one .side of the knife and vimmediately the .other vsharpening member engages :ithe other side of the knife. As shown in Fig. 2, at'the'point of engagement, the sharpening surface flrst engages 'the knife with a generally downward but partly rotating and vlongitudinal movement, very effective for sharpening purposes. `As the knife moves along, the Atip will engage ythe fleather portion where this particular portion vof vthe edge is stropped or finished. As the knife 'advancesstill further, it passes the pointat which it is engaged with the leather, and subsequently is-engaged by the grooved roller 88 to protect the edge. In this way, the entire edge o'f the knife is'subjected rst to the grinding or sharpeningactionfof thestone `and then .to the stroppng or finishing action of the leather.

On account of the support ifor the sharpening members, Athey adjust :themselves .readily .to the `position of theknife and the depth to which the knife extends down between them. When. va knifeis new, it extends iwell down ytoward the lower -portioniof the sharpening surface, but as it becomes worn, it extends down less and less. Nevertheless, the sharpening 'members .adjust themselves to this difference. Moreover, by means of the :adjusting rod 52 further .adjustment can be made.

As the carriage moves to the right in Fig. .2, the spring T9 is tensioned until the portion 69h of the latch engages the vend of .rod 14. This relases zthe latch, allowing the ,handleto `rise and at the Sametime releasing the frack 96 from the worm 94. The arm Si vhas in fthe meantimeen- .gaged the button m9 .andstopped the motor. I adjust .the position ofthe parts so that-the Ymotor is stopped just before 4the .latch Ais released, and enough movement will still taken place to release ,the latch. As soon as the rack 96 is released from worm 94, the springs '19 return the carriage to starting position and the knife, having already been released, can be removed.

In'connection with-the sharpening members, it vis to be noted that they slant in two'ways so as to accommodate the knife between them and sharpen the edge thereof on the -down stroke. The compound inclination of the vtwosharpening members is understood'byreferenoefto .,Figs. '.1 and In recent years, -knives wthremovable blades have been fo'ffered to furriers In general, they have substantially the same shape as the single piece knife, and if desired the entire knife, including Vholder and blade, lmay be placed in 'the sharpening machine; In Fig. 8, however, I-show a modified adapter 12| vformed in two partsand `adapted to engage inthe carriage 51. The blade |22 is suitably carriedvat Ethe lower part of the adapter. The blade |22 is shown in Fig. 6. A somewhat modified blade employed also in fur knivesis indicated'by thecharacter N23 in Fig. -'7. -By means of the adapter, la num'ber of 'these blades vmay be sharpened at one time and be kept 'ready for vinsertion into the holder as Ithe cutter need's them. Most cutters do not Vfavor the knife with theremovable'blade `and so I consider, as the main embodiment of my invention, thefsharpening of the conventional type of rsingle piece fur 'knife of the general character shown in'Figs. 1 and 2. v

What I claim as new and desire tov protect'by Letters Patent of the United States is:

l1. In-'a :machine for Vsharpening knives, a pair of shafts disposed generally end to'end of each other, a pairof substantially-radiallyffaced -shar'p'- ening members secured on said shafts, a plurality of composite lsharpening surfaces on said sharpening `members disposed'on said faces of the sharpening lmembers vfacing each other, and means for moving the knife, longitudinally of lits cutting edge, rbetween said sharpening members whereby to cause the-same Ato engage the edge f sharpening surfaces of `the two members to env gage the knif'ealternately, thefaces of the sharpem'ng members 'being inclined with respect to eachother and the sharpening ysurfacesl of one sharpening member-engaging between the sharpferiing'surfaces of the other sharpening member 'at onev portion of their circumference, whereby tofpermit the 'knife to lie between the sharpening members at thev opposite `portion of the circumference so that the surfaces engage the knife with a generallydownward movement. A

4. In :a ymachine-'for sharpening knives, a carriage, means for locking the knife in'sa'id carriage with the edge to be sharpened projecting downwardly therefrom, means for advancing-saidcarriage longitudinally of the knife, aV plurality of substantially radially disposed moving sharpening `surfaces engagingithe 7knifeas :it moves, and

feac'h 'sharpening Asurface having a composite sharpening and stroppingelement and positioned so1that,.as-the knife advances, the stropping ele- .ment engages the edge afterv the sharpening element, and means for returning the carriage to starting Kposition when it 'has :reached its -extreme of'travel.

i5.' In a machine for sharpeningy knives, a carriage, means for supporting aknife in said carriage with its edge projecting therefrom, a rotatable worm, a rack carried by the'carriage and adapted to be engaged by the worm, means to secure the knife in the carriage, said last-mentioned means serving to effect engagement of the rack and the worm, said carriage beingj moved longitudinally of the knife edge by the action of said worm and rack, and sharpening means engaging and sharpening the edge of the knife as the carriage advances.

6. In a machine for sharpening knives, a carriage, means for supporting a knife in said carriage with its edge projecting therefrom, a rotatable worm, a rack carried by the carriage and adapted to be engaged by the worm, means to secure the knife in the carriage, said last-mentioned means serving to effect engagement of the rack and the Worm, said carriage being moved longitudinally of the knife edge by the action of said worm and rack, sharpening means engaging and sharpening the edge of the knife as the carriage advances, and means for releasing said rack and worm when the carriage reaches its extreme of travel.

7. In a machine for sharpening knives, a carriage, means for supporting a knife in said carriage with its edge projecting therefrom, a rotatable worm, a rack carried by the carriage and adapted to be engaged by the worm, means to secure the knife in the carriage, said last-mentioned means serving to effect engagement of the rack and the worm, said carriage being moved longitudinally of the knife edge by the action of said worm and rack, sharpening means engaging and sharpening the edge of the knife as the carriage advances, means for releasing said rack and worm when the carriage reaches its extreme of travel, and means for returning the carriage and releasing the knife.

8. In a machine for sharpening knives, means for supporting a knife, means for advancing the knife longitudinally of its cutting edge, a pair of co-acting substantially radially disposed sharpening members engaging the knife edge with a motion generally away from the edge, said members having a composite sharpening and stropping surface and positioned so that, as the knife advances, the stropping surface engages the edge after the sharpening surface.

9. In a knife sharpening machine, means for supporting a knife, a pair of shafts disposed generally end to end of each other, a rotatable substantially radially faced sharpening wheel fixed to each shaft, each of said wheels having spaced composite sharpening and stropping portions thereon, the spaced composite sharpening and stropping portions on one wheel being offset from those on the other wheel, and means providing relative movement, longitudinally ofthe cutting edge of the knife, between the knife supporting means and the rotatable sharpening wheels whereby the knife is initially sharpened and then stropped.

10. In a knife sharpening machine, means for supporting a knife, a pair of rotatable substantially radially faced sharpening wheels the axes of rotation of which are set at an angle to each other whereby at least the edge portion of the knife may fit in the resulting grooved space between said sharpening Wheels, each of said wheels having spaced composite sharpening and stropping portions, the composite sharpening and stropping portions on one wheel being offset from those on the other Wheel, and means for advancing the knife on its supporting means in a direction longitudinally of the cutting edge of the knife whereby the knife is initially sharpened and then stropped.

11. In a machine for sharpening knives, a pair of shafts disposed generally end to end of each other, a substantially radially faced sharpening member secured on each of said shafts, a plurality of spaced composite sharpening and stropping surfaces disposed on faces of the sharpening members facing each other, the spaced composite sharpening and stropping surfaces on said sharpening members being in staggered relation to each other, means to rotate the shafts and sharpening members, and means for moving the knife to be sharpened between said sharpening members whereby to cause the same to engage the cutting edge of the knife and'sharpen the same, the sharpening and stropping surfaces being so arranged that the knife is initially sharpened and then stropped,

12. In a machine for sharpening knives, means for holding a knife, means for advancing the knife longitudinally of its edge, at least one grooved roller which serves to support the edge of the knife, anda pair of coacting sharpening members engaging the knife with a motion generally away from the edge, said members having a composite sharpening and stropping surface and positioned so that, as the knife advances, the stropping surface engages the edge after `the sharpening surface.

13. In a knife sharpening machine, a pair of rotatable substantially radially faced sharpening wheels each of which is mounted on an individual shaft and the axes of rotation of said wheels being set `at an angle to each other, each of said wheels having spaced composite sharpening and stropping portions thereon, the spaced composite sharpening and stropping portions on one wheel being offset from those on the other wheel whereby the knife is initially sharpened and then stropped.

14. A tool for sharpening knives comprising a body member of generally circular cross section, and a series of substantially radially disposed composite sharpening and stropping portions mounted thereon, said ,portionsV being spaced from each other.

15. A tool for sharpening knives comprising a body member of generally circular cross section and having a substantially fiat surface, said surface being provided with a series of substantially radially disposed composite sharpening and stropping portions, the sharpening portions being peripherally inset from the stropping portions, said composite portions being spaced from each other.

16. The tool as defined in claim 15, wherein the stropping portion is formed of leather.

1'7. In a knife sharpening machine, flexibly mounted means for supporting a knife, a pair of rotatable sharpening wheels the axes of rotation of which are set at an angle to each other whereby a sharpening groove is formed therebetween, each of said wheels having spaced sharpening surfaces thereon which are in staggered relation to each other, and means for automatically adjusting the extent of the sharpening groove to accommodate knives of varying depth, said last mentioned means cooperating with the flexibly mounted knife supporting means to provide said automatic adjustment.

18. The machine as defined in claim 17. Wherein the last mentioned means includes spring means.

19. A method of sharpening knives which comprises advancing the knife longitudinally of its cutting edge and in only a single forward direction between two angularly disposed substantially radially faced composite sharpening and stropping surfaces, and rotating said surfaces while advancing the knife whereby both sharpening and stropping of the knife successively take place in the order named, the sharpening and stropping strokes being in a direction generally downward and away from the body of the knife.

20. A method of sharpening knives which comprises advancing the knife longitudinally of its cutting edge between two angularly disposed substantially radially faced sharpening membershaving spaced composite sharpening and stropping surfaces in staggered relation to each other, and rotating said members while advancing the knife whereby both sharpening and stropping of the knife successively take place in the order named, the sharpening and strapping strokes being in a direction generally downward and away from the body of the knife, and the opposite sides of the knife being alternately contacted with the composite sharpening and stropping surfaces.

2l. A knife sharpening machine comprising a knife holder adapted to immovably clamp the knife blade therein and a plurality of substantially radially faced rotatable sharpening members which engage the edge of the knife to sharpen the same, said knife holder being fiexibly mounted and automatically self-adjusting to correct the position of the knife as it wears away,

or knives of varying depths, with respect to the rotatable sharpening members, said sharpening members having composite sharpening and stropping portions whereby the knife is initially sharpened and then stropped.

22. In a machine for sharpening knives, means for supporting a knife, means for advancing the knife longitudinally of its edge, and a pair of coacting rotatable sharpeningl members, each having a plurality of composite sharpening surfaces staggered with respect to each other, the knife edge being adapted to be disposed between said surfaces, and each of said composite surfaces having a sharpening and stropping portion and positioned so that, as the knife advances, the stropping surfaces engage the edge after the sharpening surfaces, and a grooved roller forward of the rotatable sharpening members in the direction of advancement of the knife, said grooved roller serving to support and protect the edge of the sharpened knife from injury.

2.3. In a machine for sharpening knives, means for supporting a knife, means for advancing the knife longitudinally of its edge, a pair of coacting sharpening members engaging the knife edge with a motion generally away from the edge, said members having a composite sharpening and stropping surface and positioned so that, as the knife advances, the stropping surface engages the edge after the sharpening surface, said knife supporting means being automatically self-adjusting to correctly position the knife as it wears away, or knives of varying depths, with respect to the coacting sharpening members.

JULIUS A. GROBSTEIN. 

